The SteriPEN Classic destroys viruses, bacteria and protozoa (giardia & cryptosporidium). The Classic SteriPEN is great for hiking, traveling, or backpacking. Includes UV Pen, Prefilter, Nalgene Bottle, and Neoprene UV Light Case. WARNING: It is strongly recommended that you use a sediment filter (like the SteriPEN FitsAll Filter) before using a UV Light for purification. The SteriPEN SP-SYS will purify up to 32 oz of water at a time. The UV lamp life will last for up to 8,000 treatments. Includes Neoprene travel case and Prefilter. The Classic Portable UV System can disinfect 1 liter of water 4 times a day for over 5 years! Batteries are NOT included. Requires 4 AA Batteries. Simply press the activation button and immerse the UV lamp into the water you are treating. The lamp will automatically emit microbe-killing Ultraviolet light.